Potential antagnosim of cultivated and wild grass–endophyte associations towards Meloidogyne incognita

Abstract

Potential antagonism towards plant-parasitic nematode Meloidogyne incognita by grass–endophyte associations and their corresponding endophytes was evaluated. The following grass-endophyte associations were studied: (1) the cultivated grass Schedonorus arundinaceus-Neotyphodium coenophialum, (2) the wild grass Leymus chinensis-Neotyphodium sp. and (3) the wild grass Achnatherum sibiricum-Neotyphodium sibiricum. The cultivated grass Schedonorus arundinaceus was used to evaluate the effect of the endophyte fungus on chemotaxis of M. incognita. The results showed a significant negative effect on chemotaxis of the second-stage juveniles (J2) of M. incognita towards S. arundinaceus-N. coenophialum plants (P<0.05). The associations of the grass S. arundinaceus-N. coenophialum and the wild grass A. sibiricum-N. sibiricum were used for testing their effect on penetration of grasses by J2. The wild grass A. sibiricum-N. sibiricum association appeared to suppress J2 penetration. N. coenophialum, Neotyphodium sp. and N. sibiricum isolated from cultivated and wild grasses respectively were used for measuring their effect on J2 mortality. Undiluted culture filtrates of all endophytic fungi caused significantly high J2 mortality 72.6% for N. coenphialum, 91.7% for Neotyphodium sp. and 66.8% for N. sibiricum. Finally, the penetration of cucumber roots by J2 pretreated by the filtrates of the three endophytic fungi was also tested. N. sibiricum filtrate significantly reduced the number of J2 penetrations by 44.5% and no significant effect in the treatment of the filtrates of Neotyphodium sp. from L. chinensis. Taken together, endophytic fungi of the genus Neotyphodium might be a potential source of biological control agents for plant parasitic nematodes.